Previous studies in our laboratory have documented the short-term superiority of anti-refluxing colonic conduits compared to freely refluxing ileal conduits in the prevention of pyelonephritis. This study is designed to evaluate the possible long term detrimental effects of reflux in urinary conduit diversion and undiversion. A group of 24 dogs will have paired refluxing or non-refluxing urinary anastomoses into colonic or ileocecal conduits. Gallium 67 citrate scans and antibody-coated bacteria will be correlated with histologic evidence (biopsy) of pyelonephritis at 3 months after diversion. Conduit cystoplasties will extend this observation period in a high pressure system to 6 months. An additional group of 8 dogs will have direct comparison of the ileocecal reinforced anastomosis versus colonic tunnelled anastomosis in the same conduit cystoplasty. Urodynamic assessment of the two types of anastomoses (Whitaker test) and direct pressure measurements of the occurrence of reflux will provide additional data on the two most commonly utilized anti-reflux procedures.